How to set a header for a HTTP GET request, and trigger file download?
JavascriptAjaxHttp HeadersDownloadJavascript Problem Overview
Update 20140702:
(but I'm marking one of the other answers as accepted instead of my own, as it got me halfway there, and to reward the effort)
It appears that setting a HTTP request header is not possible through links with <a href="...">, and can only be done using XMLHttpRequest.
However, the URL linked to is a file that should be downloaded (browser should not navigate to its URL), and I am not sure is this can be done using AJAX.
Additionally, the file being returned is a binary file, and AJAX is not intended for that.
How would one go about triggering a file download with a HTTP request that has a custom header added to it?
edit: fix broken link
Javascript Solutions
Solution 1 - Javascript
There are two ways to download a file where the HTTP request requires that a header be set.
The credit for the first goes to @guest271314, and credit for the second goes to @dandavis.
The first method is to use the HTML5 File API to create a temporary local file, and the second is to use base64 encoding in conjunction with a data URI.
The solution I used in my project uses the base64 encoding approach for small files, or when the File API is not available, otherwise using the the File API approach.
Solution:
var id = 123;
var req = ic.ajax.raw({
type: 'GET',
url: '/api/dowloads/'+id,
beforeSend: function (request) {
request.setRequestHeader('token', 'token for '+id);
},
processData: false
});
var maxSizeForBase64 = 1048576; //1024 * 1024
req.then(
function resolve(result) {
var str = result.response;
var anchor = $('.vcard-hyperlink');
var windowUrl = window.URL || window.webkitURL;
if (str.length > maxSizeForBase64 && typeof windowUrl.createObjectURL === 'function') {
var blob = new Blob([result.response], { type: 'text/bin' });
var url = windowUrl.createObjectURL(blob);
anchor.prop('href', url);
anchor.prop('download', id+'.bin');
anchor.get(0).click();
windowUrl.revokeObjectURL(url);
}
else {
//use base64 encoding when less than set limit or file API is not available
anchor.attr({
href: 'data:text/plain;base64,'+FormatUtils.utf8toBase64(result.response),
download: id+'.bin',
});
anchor.get(0).click();
}
}.bind(this),
function reject(err) {
console.log(err);
}
);
Note that I'm not using a raw XMLHttpRequest,
and instead using ic-ajax,
and should be quite similar to a jQuery.ajax solution.
Note also that you should substitute text/bin and .bin with whatever corresponds to the file type being downloaded.
The implementation of FormatUtils.utf8toBase64
can be found here
Solution 2 - Javascript
Try
html
<!-- placeholder ,
`click` download , `.remove()` options ,
at js callback , following js
-->
<a>download</a>
js
$(document).ready(function () {
$.ajax({
// `url`
url: '/echo/json/',
type: "POST",
dataType: 'json',
// `file`, data-uri, base64
data: {
json: JSON.stringify({
"file": "data:text/plain;base64,YWJj"
})
},
// `custom header`
headers: {
"x-custom-header": 123
},
beforeSend: function (jqxhr) {
console.log(this.headers);
alert("custom headers" + JSON.stringify(this.headers));
},
success: function (data) {
// `file download`
$("a")
.attr({
"href": data.file,
"download": "file.txt"
})
.html($("a").attr("download"))
.get(0).click();
console.log(JSON.parse(JSON.stringify(data)));
},
error: function (jqxhr, textStatus, errorThrown) {
console.log(textStatus, errorThrown)
}
});
});
Solution 3 - Javascript
I'm adding another option. The answers above were very useful for me, but I wanted to use jQuery instead of ic-ajax (it seems to have a dependency with Ember when I tried to install through bower). Keep in mind that this solution only works on modern browsers.
In order to implement this on jQuery I used jQuery BinaryTransport. This is a nice plugin to read AJAX responses in binary format.
Then you can do this to download the file and send the headers:
$.ajax({
url: url,
type: 'GET',
dataType: 'binary',
headers: headers,
processData: false,
success: function(blob) {
var windowUrl = window.URL || window.webkitURL;
var url = windowUrl.createObjectURL(blob);
anchor.prop('href', url);
anchor.prop('download', fileName);
anchor.get(0).click();
windowUrl.revokeObjectURL(url);
}
});
The vars in the above script mean:
- url: the URL of the file
- headers: a Javascript object with the headers to send
- fileName: the filename the user will see when downloading the file
- anchor: it is a DOM element that is needed to simulate the download that must be wrapped with jQuery in this case. For example
$('a.download-link').
Solution 4 - Javascript
i want to post my solution here which was done AngularJS, ASP.NET MVC. The code illustrates how to download file with authentication.
WebApi method along with helper class:
[RoutePrefix("filess")]
class FileController: ApiController
{
[HttpGet]
[Route("download-file")]
[Authorize(Roles = "admin")]
public HttpResponseMessage DownloadDocument([FromUri] int fileId)
{
var file = "someFile.docx"// asking storage service to get file path with id
return Request.ReturnFile(file);
}
}
static class DownloadFIleFromServerHelper
{
public static HttpResponseMessage ReturnFile(this HttpRequestMessage request, string file)
{
var result = request.CreateResponse(HttpStatusCode.OK);
result.Content = new StreamContent(new FileStream(file, FileMode.Open, FileAccess.Read));
result.Content.Headers.Add("x-filename", Path.GetFileName(file)); // letters of header names will be lowercased anyway in JS.
result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
{
FileName = Path.GetFileName(file)
};
return result;
}
}
Web.config file changes to allow sending file name in custom header.
<configuration>
<system.webServer>
<httpProtocol>
<customHeaders>
<add name="Access-Control-Allow-Methods" value="POST,GET,PUT,PATCH,DELETE,OPTIONS" />
<add name="Access-Control-Allow-Headers" value="Authorization,Content-Type,x-filename" />
<add name="Access-Control-Expose-Headers" value="Authorization,Content-Type,x-filename" />
<add name="Access-Control-Allow-Origin" value="*" />
Angular JS Service Part:
function proposalService($http, $cookies, config, FileSaver) {
return {
downloadDocument: downloadDocument
};
function downloadFile(documentId, errorCallback) {
$http({
url: config.apiUrl + "files/download-file?documentId=" + documentId,
method: "GET",
headers: {
"Content-type": "application/json; charset=utf-8",
"Authorization": "Bearer " + $cookies.get("api_key")
},
responseType: "arraybuffer"
})
.success( function(data, status, headers) {
var filename = headers()['x-filename'];
var blob = new Blob([data], { type: "application/octet-binary" });
FileSaver.saveAs(blob, filename);
})
.error(function(data, status) {
console.log("Request failed with status: " + status);
errorCallback(data, status);
});
};
};
Module dependency for FileUpload: angular-file-download (gulp install angular-file-download --save). Registration looks like below.
var app = angular.module('cool',
[
...
require('angular-file-saver'),
])
. // other staff.
Solution 5 - Javascript
Pure jQuery.
$.ajax({
type: "GET",
url: "https://example.com/file",
headers: {
'Authorization': 'Bearer eyJraWQiFUDA.......TZxX1MGDGyg'
},
xhrFields: {
responseType: 'blob'
},
success: function (blob) {
var windowUrl = window.URL || window.webkitURL;
var url = windowUrl.createObjectURL(blob);
var anchor = document.createElement('a');
anchor.href = url;
anchor.download = 'filename.zip';
anchor.click();
anchor.parentNode.removeChild(anchor);
windowUrl.revokeObjectURL(url);
},
error: function (error) {
console.log(error);
}
});